Conventionally, simulators have been designed to simulate the behavior of individual agents in a virtual environment. Here, examples of the agents include moving objects such as vehicles, motorcycles, bicycles, and pedestrians. As one example, a technique has been known that predicts traffic volumes and traffic jam occurrence states using a simulator that simulates the behavior of vehicles. Such a traffic flow simulator is capable of evaluating effects of traffic smoothness beforehand that will be obtained by traffic measures, such as infrastructure installation including road maintenance and ETC service, and therefore, is utilized as an effective tool for city planning. Further, there also is a traffic flow simulator capable of predicting an accident occurrence state by simulating recognition and judgment errors by drivers (for example, see Japanese Laid-open Patent Publication No. 2007-47972).
The traffic flow simulator reproduces a traffic state in a virtual space in the computer. Among the traffic flow simulators, a simulator that models the behavior of individual vehicles is called a microscopic traffic flow simulator, which is capable of simulating traffic flows in detail. For a large-scale simulation, a parallel distributed processing is performed using a plurality of calculator resources.
Generally, in the distributed processing in the traffic flow simulator, a space targeted for the simulation is divided to be allocated to a plurality of calculator resources, and each of the calculator resources simulates the behavior of vehicles existing in the divided space allocated to themselves. As the behavior of vehicles in the real world is determined in accordance with the surrounding circumstances (other vehicles, pedestrians, traffic signals, etc), it is necessary to refer to the surrounding circumstances (information of other vehicles, etc) for simulating the behavior of vehicles. When adjacent spaces are allocated to other calculator resources, this information should be obtained via communication.
There is a problem that an amount of communication generated between the calculator resources increases as the number of vehicles increases, which results in a decline in processing performance. Because of this, Japanese Laid-open Patent Publication No. 2005-4676 has been known as a technique that reduces the amount of communication between the calculator resources in the parallel distributed processing.